1、连接数据库的基本步骤：

2、执行数据库的插入，修改，更新，删除操作。以及对预处理操作PreparedStatement接口的查询选择操作。

代码如下：

package org.lxh.demo17.connectdemo;import java.sql.Connection;  import java.sql.DriverManager;  import java.sql.PreparedStatement;import java.sql.ResultSet;  import java.sql.Statement;//import java.sql.SQLException;  //import java.sql.Statement;  public class ConnectionDemo01{	public static void main(String[]args)throws Exception{		try{			Class.forName("org.gjt.mm.mysql.Driver");			try{							Connection connection =  DriverManager.getConnection("jdbc:mysql://localhost:3306/class2", "root", "1234");			Statement statement = connection.createStatement();	 						PreparedStatement pstmt=connection.prepareStatement("SELECT id,name,sex,age FROM stu WHERE id LIKE ? OR name LIKE ? OR sex LIKE ? OR age LIKE ?");					 //   statement.executeUpdate("INSERT INTO stu (id,name,sex,age)" + " VALUES ('5','lucy1','F','20' )");					  pstmt.setString(1,"%"+"l"+"%");		  pstmt.setString(2,"%"+"l"+"%");		  pstmt.setString(3, "%"+"l"+"%");//select中有几个问号在这里就要加上几个setString。		  pstmt.setString(4,"%"+"l"+"%");		  		  ResultSet rs=pstmt.executeQuery();		  		  while(rs.next()){			  int id=rs.getInt(1);			  String name=rs.getString(2);			  String sex=rs.getString(3);			  int age=rs.getInt(4);			 	  		 	    		  //  ResultSet resultSel = statement.executeQuery( "select * from stu" );		 //   while(resultSel.next()){		    	/*int id=resultSel.getInt("ID");		    	String name=resultSel.getString("name");		    	String sex=resultSel.getString("sex");		    	int age=resultSel.getInt("age");*/		    			  //  	int id=resultSel.getInt(1);		   // 	String name=resultSel.getString(2);		   // 	String sex=resultSel.getString(3);		  //  	int age=resultSel.getInt(4);		    			    	System.out.print("学号:"+id+"; \n");		    	System.out.print("姓名："+name+"; \n");		    	System.out.print("性别"+sex+";\n ");		    	System.out.print("年龄"+age+"; \n");	    			    }		   // statement.executeUpdate("update stu set age=30 where name='lily'");		   statement.executeUpdate("delete from userclob where name='lily'");		    		    //resultSel.close();		    //statement.close(); 		    //connection.close();		  rs.close();		  pstmt.close();		  connection.close();		    			}			catch (Exception e) {				System.out.println("数据库连接失败" + e.getMessage());  				// TODO: handle exception			}						System.out.println("success");		}catch(ClassNotFoundException e){			e.printStackTrace();		}				}}

 3、处理大数据对象（写入和读取操作）的代码还在测试中，其中输出文件的内容到测试console中显示时有问题。